1. Field of the Invention
The present invention relates to a vehicle driving system.
Priority is claimed on Japanese Patent Application No. 2012-035516, filed Feb. 21, 2012, the content of which is incorporated herein by reference.
2. Description of Related Art
As a vehicle driving system that transmits a turning force thereof while allowing differential motion between right and left axles of a vehicle, a configuration is known that includes a so-called double pinion double sun type differential mechanism (hereinafter simply referred to as a differential mechanism) having two sun gears and two pinion gears, and a drive gear that is disposed on the outer peripheral side with respect to the differential mechanism and inputs power from the driving power source to the differential mechanism (for example, refer to German Patent Application, Publication No. 102007004710).
More specifically, the differential mechanism includes first and second sun gears which are respectively fixed to both axles, a first pinion gear which is engaged to the first sun gear, a second pinion gear which is engaged to the second sun gear and the first pinion gear and a carrier which rotatably supports the first pinion gear and the second pinion gear. The carrier has a bearing portion which rotatably supports the first pinion gear and the second pinion gear, and a mounting piece which is disposed out of phase with respect to the bearing portion.
The drive gear is arranged so as to enclose the outer side of the carrier in the radial direction, and a gear portion for transmitting the driving power of the driving power source to the carrier is formed on the outer peripheral surface thereof. In addition, on the inner peripheral surface of the drive gear, the mounting piece is disposed to protrude inward in the radial direction.
Then, in a state where the mounting piece of the differential mechanism and the mounting piece of the drive gear are placed face-to-face in the axial direction, the differential mechanism and the drive gear are fixed by fastening members such as bolts. Accordingly, the driving power of the drive gear is configured to be transmitted to the carrier as a friction force between the respective mounting pieces or a shearing force to the fastening members.